There is an optical type record card called memory card, a software card or the like. A prior art card of this kind will be described first with reference to FIG. 11. Reference numeral 1 generally designates an optical type record card. In this card 1, a main track T.sub.M of a band-shape is formed rectilinearly on a rectangular card substrate (record medium) 1A along its longitudinal direction. The main track T.sub.M is formed of the alignment of a plurality of sub-tracks T.sub.S which are parallel to each other. Further, each sub-track T.sub.S is formed of the alignment of pits P as a plurality of optical dot-shaped recorded marks as shown in FIG. 12. Each sub-track T.sub.S is located perpendicularly to its alignment direction, that is, the longitudinal direction of the main track T.sub.M. On each sub-track T.sub.S, there is recorded a unit signal amount of a digitized signal of an information signal such as, video, audio, data signals and the like on the basis of the presence or absence of the pit P and the difference of the spacing between the pits.
Although the pit P is a concavity on a light reflection layer formed on the card substrate 1A, as an optical dot-shaped recorded mark, it may be possible to obtain a recorded mark formed on the basis of the difference between light reflectivities provided by the phase transfer between the crystal and amorphous on a layer of, for example, TeOx.sub.(x.apprxeq.1).
Reference numerals 1a and 1b designate both side edges of the card substrate 1A and which are formed as the straight lines parallel to the main track T.sub.M. One side edge 1a is taken as a reference side edge. The respective side surfaces at both the side edges 1a and 1b of the card substrate 1A construct the planes perpendicular to the front and back surfaces of the card substrate 1A which are made parallel to each other.
Subsequently, an optical type record card reader for reading from the card 1 the information signal recorded on the main track T.sub.M will be described with reference to FIGS. 13 and 14. The card 1, which is entered through the insertion slot to the inside of the reader, is transported along the reference side edge 1a of the card 1 to the direction shown by an arrow 3 by card transport rollers 2. An irradiation light 5 from a light source 4 irradiates the track T.sub.M of the card 1 through a condenser lens 6 and a reflected light from the track T.sub.M, that is, a read light 7 of the track T.sub.M is irradiated through a focusing lens 8 to a line sensor 10 supported by a supporting plate 9, whereby the information signal is read out. The line sensor 10 is formed of a CCD (charge coupled device). This is formed such that a plurality of detection elements 10a are arranged rectilinearly and from which an image projected thereon is read out by the electronic scanning. On the line sensor 10, the longitudinal direction of the image of the sub-track T.sub.S coincides with the alignment direction of the detection elements 10a and images P' of all the pits P of one sub-track T.sub.S are focused simultaneously on the photo detector 10 so that the information signal of one sub-track T.sub.S amount is read out at the same time.
FIG. 15 shows a corresponding relationship between the line sensor 10 and the images P' of the pits P projected thereon.
By the way, while the optical type record card 1 is being transported, if the projected image of the sub-track T.sub.S to the line sensor 10 has an azimuth error relative to the line sensor 10, it becomes impossible to read the information of the sub-track T.sub.S.
Therefore, in the prior art, the azimuth error is corrected, that is, the azimuth error is reduced to zero by rotating the line sensor 10. In this case, in practice, the substrate on which the line sensor 10, its driver, amplifier and the like are mounted must be rotated. In addition, because of the presence of the cords for the power source and the signal, it is very difficult to correct the azimuth error by rotating the line sensor 10 smoothly, highly precisely and rapidly.
In view of such aspect, the present invention is to provide the optical type record card reader which can correct the azimuth error of the projected image of the sub-track on the optical type record card to the line sensor smoothly, highly precisely and rapidly.